Ribbed V-belts are also referred to as Poly-V-belts and widely used for realizing a belt drive in motor vehicles, particularly for driving ancillary units or auxiliary equipment. Belt drives of this type make it possible to drive auxiliary equipment or ancillary units such as a cooling pump, an air-conditioning compressor, a generator, a power steering pump and the like by means of the main unit such as, e.g., the driving side of the crankshaft of an engine. V-belts, ripped V-belts or Poly-V-belts frequently are statically tensioned or may feature automatic tensioning systems, in particular, in order to observe a largely constant belt tension.
In conventional belt drives, the belt tension is realized such that a sufficiently reliable torque transmission between the pulleys on the driven side and the driving side of the belt can be ensured for all conceivable operating states of the belt drive. Auxiliary equipment that can be deactivated or variably activated such as, for example, the air-conditioning compressor of an air-conditioning system result in an at least brief peak load at the time of their activation in the belt drive.
Furthermore, rotational irregularities, i.e., deviations from an average angular velocity of a crankshaft on the driven side, can occur, in particular, in the low-speed range of an internal combustion engine. Such peak loads or rotational irregularities only occur relatively rarely and for brief periods of time, but require a comparatively high belt tension. In order to also take into account such boundary states and to ensure a sufficient torque transmission when an air-conditioning compressor is activated or rotational irregularities occur, the tension of the ribbed V-belt needs to be standardly defined for this boundary situation and permanently adjusted to a comparatively high tension level.
The thus far conventional, comparatively high tension of a Poly-V-belt or a ribbed V-belt is associated with increased friction losses, as well as a relatively high mechanical load on the bearings of participating pulleys. This not only results in an increased fuel consumption, but also a reduced service life of the ribbed V-belt or the pulleys and the corresponding bearings of the ancillary units that are functionally connected to the ribbed V-belt.
In this respect, at least one aim is to make available an improved tensioning device for a ribbed V-belt of a motor vehicle that makes it possible to extend the service life of the ribbed V-belt, as well as to reduce the mechanical load on the participating pulleys and their bearings. At least another aim is lowering the fuel consumption of an internal combustion engine. In addition, it should be possible to easily realize the tensioning device with respect to its construction and manufacturing technology. In addition, other aims, desirable features and characteristics will become apparent from the subsequent summary and detailed description, and the appended claims, taken in conjunction with the accompanying drawings and this background.